Radiation therapy and diagnostic imaging equipment are used frequently in hospitals and treatment centers. Modern techniques for radiation therapy and diagnostic imaging require that patients be positioned and immobilized precisely. Generally, treatment of a tumor by radiation therapy is preceded by a diagnostic imaging procedure called simulation. During simulation, the patient is positioned in the manner anticipated for treatment. This includes the physical orientation of the patient using the positioning and immobilization devices that will be used in treatment. In this manner, the computer data set of the patient (DICOM) contains an accurate representation of the location of the tumor. That data set is then imported into treatment planning software (TPS) so that the treatment can be modeled and planned. It is critical that the patient be simulated in precisely the same position on the same devices as will be used in treatment to ensure accurate tumor location identification for treatment. Accurate tumor location and treatment spares the surrounding healthy tissue.
This patient positioning and immobilization process can be extensive and time consuming. It is beneficial, therefore, to set up the patient beforehand on a device other than the actual treatment or imaging device to better utilize time on the treatment or imaging equipment. In some cases imaging and treatment are done on the same day. In these cases it is beneficial to set up the patient once and have them remain immobilized throughout the imaging and treatment procedures.
When transporting patients from one piece of equipment to another, it is highly desirable to employ a low friction transfer system. Such a device enables the safe and efficient transfer of a patient from one target modality to another. By placing an air bearing between the patient support surface and supporting structure (e.g. CT couch, Linear accelerator couch, trolley), the patient can be moved easily and safely. An easy and safe transfer is beneficial for both the patient and the operator moving the patient.
Existing air bearing technologies suffer in that they either raise the patient surface too high when inflated or they are not uniformly radiolucent. By inflating a large area, existing systems cause a series of problems; they take up too much height which limits patient access to machines, they jostle the patient causing inaccuracies to occur in the patient's position, and they are unstable causing them to be unsafe and uncomfortable for the patient. The lack of uniformity or homogeneity under x-ray means that x-ray artifacting occurs when images are taken of the patient. Lack of uniformity can also hinder or make it impossible to treat through the system with high-energy x-radiation (such as linear accelerators) or particle beam radiation (such as proton therapy). Extremely low attenuation and homogeneity is required for transport systems to work properly in these environments.
A desirable low friction transfer system must be compatible with a variety of imaging and treatment modalities. It is also beneficial to use the same devices for radiation treatment and diagnostic imaging. By using the same device, hospitals and treatment centers can have better utilization of equipment and higher patient throughput. This in turn lowers cost and provides faster patient care.